Amy Williams is a 31-year-old living in Myrtle Beach, South Carolina. In August 2005, she gave birth to a healthy baby boy, Christian Millare.

Amy Williams

But Christian didn't live long. He died in January 2008 at age 2 of a fatal seizure, after suffering from them for most of his life.

Now, his mother believes his death could have been prevented if not for what she calls an erroneous DNA test result by one of the world’s largest laboratories — which she’s suing.

Amy Williams

The lawsuit was filed in February, and of last week is pending in U.S. District Court in South Carolina.

The year before he died, Christian took a DNA test made by Athena Diagnostics (now owned by Quest Diagnostics), according to the complaint.

Amy Williams

Doctors were wondering if Christian had Dravet syndrome, a rare disorder usually caused by mutations in a gene called SCN1A, according to the lawsuit.

The test result said Christian had a “variant of unknown significance” on that gene. By Athena’s definition, such variants can affect normal gene activity but “often have no effect.”

So doctors thought Christian might have had a mitochondrial disorder, a type of disease that's partly or fully inherited from the mother, according to Williams' lawsuit.

They kept giving him sodium channel-blocking medications, which help with non-Dravet seizures — but have been found to worsen Dravet in people who have it.

Although Christian's doctors saw the 2007 lab report, Williams says she didn't at the time. For years, she thought that she had given a mitochondrial disease to her son.

Amy Williams

“I didn’t think I had a right to grieve for Christian — it was my fault he died,” she told BuzzFeed News.

Then in late 2014 and early 2015, with the help of a friend knowledgeable about biology, Williams got a copy of the 2007 report, as well as a copy of a new, revised version. The 2015 report officially stated that he had a mutation that could cause disease, which is a more urgent classification than a "variant of unknown significance," according to the complaint.

Williams and her attorneys say Athena should have recognized that Christian had a "disease-associated mutation" back in 2007.

Amy Williams

That's because by the time the report came out, according to the lawsuit, there was scientificresearch showing that people carrying Christian’s specific SCN1A mutation had Dravet syndrome. There were also patentsused for diagnostic tests of such mutations, according to the complaint.

What’s more, a scientist on one of those papers was a top lab director for Athena, and had signed off on Christian’s DNA test report. The scientist, Sat Dev Batish, “clearly knew or should have known that a mistake was apparent,” according to the complaint.

The attorneys counter that the 2007 report made clear that the labs needed DNA from Christian’s mother and father to confirm their son’s test results, which otherwise “cannot be definitively interpreted.”

They also point out that the report stated that Dravet was a “possible” outcome. For nine years, according to the motion, the parents ignored an “explicit written notice” that these samples were “strongly recommended” for a complete diagnosis.

“Instead, she brings this lawsuit almost a decade later and attempts to plead around the statute of limitations and statute of repose,” the attorneys wrote of Williams.

The motion says that Williams' complaint failed to establish a factual basis for the complaint and failed to plead fraud with sufficient detail, among other things. An attorney for the companies declined to talk to BuzzFeed News about the case.

Pediatric neurologist Max Wiznitzer wrote in an affidavit on the plaintiffs' behalf that if Christian’s condition had been properly diagnosed and treated, he “would not have suffered the fatal seizure on January 5, 2008.”

Amy Williams

“My guilt has gone from ‘I gave Christian a mitochondrial disorder’ to knowing that I, every night, gave my child medicine that was making him worse,” Williams said.